Ceramic matrix composites (CMC) are used for components in high temperature environments, such in gas turbine engines. CMC is formed by combining ceramic fibers with a ceramic matrix, and heating the combined material to a sintering temperature. The fibers add tensile strength in the directions of the fibers. The resulting material has a higher operating temperature range than metal, and can be optimized for strength by fiber orientations and layering.
CMC laminate fabrication from ceramic 2D broadloom fabrics is a standard industry practice. For such laminates, a design-limiting aspect is the interlaminar tensile and shear strength of the material. This is especially true for load-bearing structures, wherein loads are reacted through CMC wall intersections or flanges.
FIG. 1 illustrates a prior art CMC structure 20, with layers of ceramic fibers or fabric 22 impregnated with a ceramic matrix 24, forming a first wall 26 and a second wall 28. The two walls are joined at an intersection 34 with a rounded outer edge 30 and an inside fillet 32. Relative bending moments between the two walls 26, 28 concentrate stresses in the intersection 34, which tends to separate the layers therein. In some gas turbine components, a ceramic thermal insulation layer 36 is applied to a surface 38 of the CMC.
Prior metal components such as brackets have been strengthened using gussets in wall intersection areas. A metal edge may be bent inward to form a gusset or diagonal brace between two wall portions. This has not been done for CMC components.